Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 1301

June 28, 20124 counties in Kansas; 38 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 28, 2012, 10:24 PM CDT for 4 counties in Kansas; 38 counties in Nebraska. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Jun 28, 2012, 10:24 PM CDT (03:24 UTC)
Expired
Jun 28, 2012, 11:30 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 42 counties

Decatur County, KS, Norton County, KS, Phillips County, KS, Smith County, KS, Adams County, NE, Boone County, NE, Buffalo County, NE, Clay County, NE, Custer County, NE, Dawson County, NE, Fillmore County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Garfield County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Hayes County, NE, Hitchcock County, NE, Howard County, NE, Kearney County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Merrick County, NE, Nance County, NE, Nuckolls County, NE, Perkins County, NE, Phelps County, NE, Platte County, NE, Polk County, NE, Red Willow County, NE, Sherman County, NE, Thayer County, NE, Valley County, NE, Webster County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 98 km from the middle of the area, began a volume at 03:28 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 3.4 hours before the alert went out and 105 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, N. Platte/Lee Bi, NE at 00:00Z on 2012-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1037 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, N. Platte/Lee Bi, NE at 00:00Z on 2012-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1037 J/kg
Mixed-layer CIN
-216 J/kg
Mixed-layer LCL
2810 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

979 
ACUS11 KWNS 290324
SWOMCD
SPC MCD 290324 
NEZ000-KSZ000-290430-

MESOSCALE DISCUSSION 1301
NWS STORM PREDICTION CENTER NORMAN OK
1024 PM CDT THU JUN 28 2012

AREAS AFFECTED...PARTS OF NWRN KS AND INTO S CENTRAL NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 290324Z - 290430Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...EVOLVING CONVECTION ACROSS NWRN KS/SWRN NEB IS SHOWING
LIMITED ORGANIZATION ALONG THE LEADING EDGE OF A DEVELOPING COLD
POOL.  SOME INCREASE IN DAMAGING WIND POTENTIAL IS EVIDENT...THOUGH
WW REMAINS UNLIKELY ATTM.

DISCUSSION...EVENING RADAR DATA HAS REVEALED A VERY SLOW INCREASE IN
CONVECTIVE COVERAGE ACROSS NWRN KS AND ADJACENT SWRN NEB OVER THE
PAST COUPLE OF HOURS...NEAR AND JUST N OF A W-E SURFACE BAROCLINIC
ZONE NEAR THE KS/NEB BORDER AS A LOW-LEVEL JET INCREASES ACROSS THIS
AREA.  

EVENING RAOBS REVEAL A DRY LOWER TROPOSPHERE TOPPED BY SUBSTANTIAL
ELEVATED CAPE...BUT THE MARGINAL KINEMATIC ENVIRONMENT -- SUPPORTIVE
OF ONLY MODEST STORM-SCALE ORGANIZATION -- WOULD SUGGEST
ISOLATED/EVAPORATIVELY INDUCED GUSTY WINDS TO BE THE PRIMARY THREAT
WITH A STRONGER STORM OR TWO.  HOWEVER...SOME EVIDENCE OF AN ENEWD
COLD POOL SURGE -- ARISING FROM THE INCREASINGLY WIDESPREAD
CONVECTION -- IS INDICATED ACROSS THE DISCUSSION AREA ATTM.  WITH
ADDITIONAL CONVECTIVE COVERAGE INCREASE POSSIBLE IN CONJUNCTION WITH
THE STRENGTHENING LOW-LEVEL JET...A ZONE OF SLIGHTLY MORE
CONCENTRATED THREAT FOR LOCALLY DAMAGING GUSTS COULD EVOLVE ACROSS
THIS AREA IN THE NEXT COUPLE OF HOURS.  WHILE WW IS NOT ANTICIPATED
ATTM GIVEN LINGERING DOUBTS WITH RESPECT TO POTENTIAL FOR ADDITIONAL
CONVECTIVE ORGANIZATION...ANY SIGNS THAT FURTHER DEVELOPMENT OF
SUSTAINED UPDRAFTS ALONG THE COLD POOL SURGE IS OCCURRING COULD
WARRANT CONSIDERATION OF WW ISSUANCE.

..GOSS/HART.. 06/29/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...OAX...TOP...GID...LBF...GLD...

LAT...LON   40109734 39420019 39690086 40860166 41440224 42069919
            41629726 40109734

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 29, 7:59 AM CDTMesoscale DiscussionSPCBoyd, Cedar91 min

Nearby

Mesoscale Discussions in Nebraska, 2012Mesoscale Discussions in Kansas, 2012Every mesoscale discussion in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.